Advanced oxidation protein products as a biomarker of cutaneous lupus erythematosus complicated by nephritis: a case-control study

Oxidative stress is involved in the pathogenesis of lupus nephritis (LN). The current study investigated the significance of advanced oxidation protein products (AOPPs) as a biomarker of LN in patients with cutaneous lupus erythematosus. Ninety-two patients who initially presented with systemic lupus erythematosus were divided into the LN- and LN+ groups. Serum AOPP levels were determined, and the association between AOPP levels and LN was investigated in a case-control study. In the LN+ group, patients with higher AOPP levels exhibited higher levels of dsDNA and proteinuria but lower levels of eGFR and complement C3 compared to those in patients with lower AOPP levels. A multivariable logistic regression model showed that the AOPP level was an independent risk factor for LN. The risk of nephritis specifically increased 24% for each 10 μM increase in AOPP (95% confidence interval, 1.166-1.915, P = 0.030). In contrast, neither elevated dsDNA level nor decreased complement C3 level was an independent risk factor for LN. Higher serum AOPP levels were associated with an increased risk of LN. Therefore, future studies are warranted to determine the potential clinical value of this novel biomarker.

Axicon on a gradient index lens (AXIGRIN): integrated optical bench for Bessel beam generation from a point-like source

We propose and demonstrate a novel concept of a compact optical component aimed at transforming a point-like source into a Bessel beam. This component, called AXIGRIN, consists of an axicon fabricated at the end facet of a gradient index lens. It can be directly coupled to an optical fiber, a microscope objective, or vertical-external-cavity surface-emitting-laser to be used without preliminary adjustments, which is of practical interest for end users. This opens new avenues in domains, such as imaging, particle acceleration and manipulation, optical coherence tomography, data storage, laser cutting, etc. AXIGRIN also opens the perspective of using Bessel beams for endoscopy. The generation of linearly and radially polarized Bessel beams is demonstrated with a fiber AXIGRIN.

Sevoflurane inhibits neurogenesis and the Wnt-catenin signaling pathway in mouse neural progenitor cells

Recent population studies suggest that children who receive anesthesia and surgery could be at an increased risk for developing learning disabilities. The underlying reason for this clinical observation is largely unknown. Whether undergoing anesthesia contributes to learning disability development, or if the need for anesthesia and surgery is a marker for other unidentified factors that contribute to the development of learning disabilities, remains to be determined. Neurogenesis, regulated by the Wnt-catenin signaling pathway, has been shown to be involved in learning and memory, and sevoflurane is the most commonly used inhalation anesthetic in children. We therefore set out to determine the effects of sevoflurane on neurogenesis and the Wnt-catenin signaling pathway in mouse neural progenitor cells (NPCs) using immunofluorescence and Western blot analysis. Here we show for the first time that 4.1%, but not 2.0%, sevoflurane reduced mouse NPC proliferation, increased Glycogen synthase kinase-3β(GSK-3β) levels, and decreased levels of β-Catenin in mouse NPCs. The GSK-3β inhibitor Lithium attenuated the sevoflurane-induced reduction in mouse NPC proliferation. The data suggest that sevoflurane may reduce neurogenesis through the Wnt-catenin signaling pathway. These findings would promote further studies to investigate the effects of anesthesia on neurogenesis and function of learning and memory, as well as the underlying mechanisms in vitro and in vivo. Ultimately these efforts would lead to safer anesthesia care and better postoperative outcomes in children.

Isoflurane induces endoplasmic reticulum stress and caspase activation through ryanodine receptors

BACKGROUND

Isoflurane has been reported to induce caspase-3 activation, which may induce neurotoxicity and contribute to the pathogenesis of Alzheimer's disease. However, the underlying mechanism is largely unknown, especially whether or not isoflurane can induce ryanodine receptors (RyRs)-associated endoplasmic reticulum (ER) stress, leading to caspase-3 activation. We therefore assessed the effects of isoflurane on RyRs-associated ER stress.

METHODS

We treated primary neurones from wild-type (C57BL/6J) mice with 1% and 2% isoflurane for 1, 3, or 6 h. We then measured levels of C/EBP homologous protein (CHOP) and caspase-12, two ER stress markers, using immunocytochemistry staining and western blotting analysis. Dantrolene (5 μM), the antagonist of RyRs, was used to investigate the role of RyRs in the isoflurane-induced ER stress and caspase-3 activation.

RESULTS

Isoflurane 2% for 6 h treatment increased the levels of CHOP (876% vs 100%, P=0.00009) and caspase-12 (276% vs 100%, P=0.006), and induced caspase-3 activation in the neurones. The administration of 2% isoflurane for 3 h (shorter duration), however, only increased the levels of CHOP (309% vs 100%, P=0.003) and caspase-12 (266% vs 100%, P=0.001), without causing caspase-3 activation. The isoflurane-induced ER stress (CHOP: F=16.64, P=0.0022; caspase-12: F=6.13, P=0.0383) and caspase-3 activation (F=32.06, P=0.0005) were attenuated by the dantrolene treatment.

CONCLUSIONS

These data imply that isoflurane might induce caspase-3 activation by causing ER stress through RyRs, and dantrolene could attenuate the isoflurane-induced ER stress and caspase-3 activation. Further investigations of the potential neurotoxicity of isoflurane are needed.

miR-34a targets the inhibin beta B gene, promoting granulosa cell apoptosis in the porcine ovary

During ovarian follicular growth and development, only a few follicles actually ovulate. Recently, it was found that follicular atresia is triggered by granulosa cell apoptosis, but the molecular mechanism of follicular atresia was not understood. Using flow cytometry, we found that miR-34a promotes granulosa cell apoptosis in pig ovarian follicles. In addition, inhibin beta B was found to be a miR-34a target gene, based on luciferase reporter assays, quantitative RT-PCR and Western blotting. Taken together, our data indicate that miR-34a plays an important role in granulosa cell apoptosis by targeting the INHBB gene in the porcine ovary.

Synthesis and photovoltaic properties of new donor–acceptor (D–A) copolymers based on benzo[1,2-b:3,4-b′:6,5-b′′] trithiophene donor and different acceptor units (P1 and P2)

A power conversion efficiency of about 5.26% has been achieved for the device based onP1:PC71BM.

Abstract P2-09-21: Teriflunomide, an immunomodulatory drug, exerts anticancer activity in triple-negative breast cancer (TNBC) cells via modulation of multiple cell signal pathways

Background: Breast cancer is the most diagnosed female cancer and the second leading cause of cancer death in the United States. Triple negative breast cancer (TNBC), a special subtype, defined as breast cancer lacking estrogen, progesterone and HER-2 receptors, showed clinically aggressive features and was associated with poor prognosis. TNBC is resistant to endocrine or HER-2 targeted therapies, and only conventional chemotherapeutic regimens were accepted as the treatment guidelines. Therefore, searching for novel pharmaceutical agents for TNBC is urgent and a hot spot in present clinical research. Teriflunomide, an orally available immunomodulatory drug, approved for treatment of multiple sclerosis (MS) by FDA, has demonstrated the potential application in cancer therapy, such as chronic lymphocytic leukemia (CLL), prostate cancer and melanoma. Therefore, we assessed the therapeutic value of teriflunomide in TNBC cells.

Methodology/Principal Findings: In this study, we showed that teriflunomide treatment resulted in a dose- and time-dependent inhibition of proliferation in three TNBC cell lines: MDA-MB-231, MDA-MB-468 and BT549. Meanwhile, the agent could also induce loss of clonogenic survival in dose-dependent fashion in TNBC cells. The analysis of cell cycle distribution by flow cytometry revealed that teriflunomide for 48 h entrapped TNBC cells in S-phase with concomitant reduction in both G1- and G2/M-phase. Furthermore, by Annexin-V/PI staining, we showed high doses of teriflunomide for 2 days led to significant necrosis and minor apoptosis in TNBC cells. Additionally, the effect of teriflunomide on TNBC cell migration and invasion was also tested using Boyden chamber assays. Short-term treatment of teriflunomide decreased the cell motility and invasiveness considerably in a concentration-dependent manner. When evaluated for underlying mechanisms, teriflunomide was found to modulate multiple cell signaling pathways in three TNBC cell lines. First, teriflunomide inhibited expression of proteins linked to cell proliferation, such as cyclin D1 and c-Myc. Second, teriflumomide delayed cell cycle transition by up-regulating cyclin A, along with p27 down-regulation and unchanged cyclin B1. Third, teriflunomide regulated the cell survival proteins, such as up-regulation of BAX and down-regulation of Bcl-Xl, by activation of MAPK pathway. Fourth, teriflunomide suppressed the marker signals involved in epithelial–mesenchymal transition(EMT) and invasion and inhibited activation of FAK/Src complex. Fifth, teriflunomide down-regulated growth factor receptors involved in TNBC growth maintenance, such as EGFR, IGF1R and FGFR4.

Conclusion/Significance: Teriflunomide, although an anti-inflammatory agent, is a potent inhibitor of TNBC cells through modulation of multiple signaling pathways and may be of therapeutic benefit for TNBC in clinical practice.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-09-21.

Screening differential expression of serum proteins in AFP-negative HBV-related hepatocellular carcinoma using iTRAQ -MALDI-MS/MS

Hepatocellular carcinoma(HCC) is serious condition associated with a high morbidity and mortality. Therefore is an urgent need to develop novel noninvasive techniques for early diagnosis, particularly for patients with AFP-negative [AFP(-)] HCC. In this study, iTRAQ-MALDI-MS/MS was used to identify differentially expressed proteins in AFP(-) HBV-related HCC compared with non-cancerous hepatitis B virus (HBV) and healthy controls subjects.Serum was obtained from 18 patients with AFP(-) HBV-related HCC, 18 matched patients with HBV without HCC and 18 healthy control subjects. High abundance proteins were removed from serum and the differentially expressed proteins from the three groups were screened out using iTRAQ-MALDI-MS/MS. The Gene Ontology (GO) function and the interaction networks of differentially expressed proteins were then analyzed. A total of 24 expressed differential proteins associated with AFP(-) HBV-related HCC were screened out, 15 proteins were up-regulated and 9 down-regulated. The most common molecular function of the 24 differentially expressed proteins was enzyme inhibition. Interaction network of the 24 differentially expressed proteins showed that 14 proteins (C5, KNG1, FN1, LRG1, HRG, SERPINC1, CRP, APOB, SAA1, APCS, C4BPA, CFI, CFB and GSN) were central to the functional network. The expression levels of the GSN protein were down-regulated in AFP(-) HBV-related HCC subjects compared with healthy controls and the HBV group (p<0.01), consistent with the iTRAQ results.The 14 proteins from the serum of AFP(-) HBV-related HCC appeared at the fulcrum of the functional network and were differentially expressed compare to HBV and healthy controls suggesting a possible association with HCC progression.

Isoflurane facilitates synaptic NMDA receptor endocytosis in mice primary neurons

Inhalation anesthetic isoflurane has been reported to induce caspase activation and accumulation of β-amyloid (Aβ), however, the down-stream consequences of these effects are largely unknown. Isoflurane has also been shown to impair learning and memory, however, the up-stream mechanisms of these effects remain largely to be determined. Facilitation of synaptic NMDA receptor endocytosis can reduce synaptic function, leading to learning and memory impairment. We therefore set out to determine the effects of isoflurane on synaptic NMDA receptor endocytosis. Primary neurons from wild-type and Alzheimer's disease transgenic mice were treated with 2% isoflurane for six hours. Synaptic surface levels of NMDA receptor 2B (NR2B) and NR2B internalization were determined by surface and cleavable biotinylation assay, western blot analysis and immunofluorescence. Here we show that isoflurane can induce caspase-3 activation, increase levels of β-site amyloid precursor protein-cleaving enzyme and cause accumulation of Aβ in the primary neurons. Isoflurane facilitates synaptic NR2B endocytosis as evidenced by reducing surface NR2B levels, increasing NR2B internalization, and decreasing the ratio of synaptic surface NR2B to synapsin in mice primary neurons. Moreover, caspase activation inhibitor Z-VAD and γ-secretase inhibitor L-685,458 attenuated the isoflurane-facilitated NR2B endocytosis. These results suggest that isoflurane induces caspase activation and Aβ accumulation, leading to facilitation of synaptic NMDA receptor endocytosis, which potentially serve as the upstream mechanism of the isoflurane-induced impairment of learning and memory. These findings will encourage further studies to determine the underlying mechanism by which isoflurane and other anesthetics promote Alzheimer's disease neuropathogenesis and induce cognitive dysfunction.

Streptococcal co-infection augments Candida pathogenicity by amplifying the mucosal inflammatory response

Mitis-group streptococci are ubiquitous oral commensals that can promote polybacterial biofilm virulence. Using a novel murine oral mucosal co-infection model we sought to determine for the first time whether these organisms promote the virulence of C. albicans mucosal biofilms in oropharyngeal infection and explored mechanisms of pathogenic synergy. We found that Streptococcus oralis colonization of the oral and gastrointestinal tract was augmented in the presence of C. albicans. S. oralis and C. albicans co-infection significantly augmented the frequency and size of oral thrush lesions. Importantly, S. oralis promoted deep organ dissemination of C. albicans. Whole mouse genome tongue microarray analysis showed that when compared with animals infected with one organism, the doubly infected animals had genes in the major categories of neutrophilic response/chemotaxis/inflammation significantly upregulated, indicative of an exaggerated inflammatory response. This response was dependent on TLR2 signalling since oral lesions, transcription of pro-inflammatory genes and neutrophil infiltration, were attenuated in TLR2(-/-) animals. Furthermore, S. oralis activated neutrophils in a TLR2-dependent manner in vitro. In summary, this study identifies a previously unrecognized pathogenic synergy between oral commensal bacteriaand C. albicans. This is the first report of the ability of mucosal commensal bacteria to modify the virulence of an opportunistic fungal pathogen.

Duplicated CCAAT/enhancer-binding protein β (C/EBPβ) gene: transcription and methylation changes in response to dietary betaine in Landes goose liver

The CCAAT/enhancer-binding protein β gene (C/EBPβ) is one of the key regulating factors of lipid metabolic balance in the liver. To better understand how C/EBPβ affects lipid accumulation in the Landes goose liver, its DNA was cloned. The goose C/EBPβ DNA sequence (2,075 bp) contains a 984-bp open reading frame and part of the 5'-flanking region, and shares 96.66 and 62.07% similarity with the chicken and human sequences at the amino acid level, respectively. Tissue expression profiling showed that the relative expression level was high in the liver and adipose tissue. To understand the effect of betaine on C/EBPβ in goose liver, the relative expression levels of C/EBPβ were detected under different treatments. Compared with the control group, C/EBPβ expression increased in the high-carbohydrate group (P < 0.01) and decreased in the betaine treatment group (P > 0.05). Using bisulfite sequencing PCR, the gene methylation status was analyzed among the different treatment groups. None of the 54 CpG sites in the promoter region or the 28 CpG sites in the structural domain of the coding region showed any significantly different methylation patterns among the groups. Taken together, the results showed that betaine decreased the goose C/EBPβ gene expression, but did not directly regulate its methylation. The data may form the basis for further investigation of the mechanisms of the effect of C/EBPβ on the regulation of lipometabolism in the goose liver and the effect of betaine on lipid metabolic genes at the molecular level.

Isoflurane affects the cytoskeleton but not survival, proliferation, or synaptogenic properties of rat astrocytes in vitro

BACKGROUND

More than half of the cells in the brain are glia and yet the impact of general anaesthetics on these cells is largely unexamined. We hypothesized that astroglia, which are strongly implicated in neuronal well-being and synapse formation and function, are vulnerable to adverse effects of isoflurane.

METHODS

Cultured rat astrocytes were treated with 1.4% isoflurane in air or air alone for 4 h. Viability, proliferation, and cytoskeleton were assessed by colorimetric assay, immunocytochemistry, or a migration assay at the end of treatment or 2 days later. Also, primary rat cortical neurones were treated for 4 days with conditioned medium from control [astrocyte-conditioned media (ACM)], or isoflurane-exposed astrocytes (Iso-ACM) and synaptic puncta were assessed by synapsin 1 and PSD-95 immunostaining.

RESULTS

By several measures, isoflurane did not kill astrocytes. Nor, based on incorporation of a thymidine analogue, did it inhibit proliferation. Isoflurane had no effect on F-actin but reduced expression of α-tubulin and glial fibrillary acidic protein both during exposure (P<0.05 and P<0.001, respectively) and 2 days later (P<0.01), but did not impair astrocyte motility. ACM increased formation of PSD-95 but not synapsin 1 positive puncta in neuronal cultures, and Iso-ACM was equally effective.

CONCLUSIONS

Isoflurane decreased expression of microtubule and intermediate filament proteins in astrocytes in vitro, but did not affect their viability, proliferation, motility, and ability to support synapses.

Anaesthetic neurotoxicity and neuroplasticity: an expert group report and statement based on the BJA Salzburg Seminar

Although previously considered entirely reversible, general anaesthesia is now being viewed as a potentially significant risk to cognitive performance at both extremes of age. A large body of preclinical as well as some retrospective clinical evidence suggest that exposure to general anaesthesia could be detrimental to cognitive development in young subjects, and might also contribute to accelerated cognitive decline in the elderly. A group of experts in anaesthetic neuropharmacology and neurotoxicity convened in Salzburg, Austria for the BJA Salzburg Seminar on Anaesthetic Neurotoxicity and Neuroplasticity. This focused workshop was sponsored by the British Journal of Anaesthesia to review and critically assess currently available evidence from animal and human studies, and to consider the direction of future research. It was concluded that mounting evidence from preclinical studies reveals general anaesthetics to be powerful modulators of neuronal development and function, which could contribute to detrimental behavioural outcomes. However, definitive clinical data remain elusive. Since general anaesthesia often cannot be avoided regardless of patient age, it is important to understand the complex mechanisms and effects involved in anaesthesia-induced neurotoxicity, and to develop strategies for avoiding or limiting potential brain injury through evidence-based approaches.

First Report of Crown Gall, Caused by Agrobacterium tumefaciens on Soapberry (Sapindus delavayi) in China

Soapberry (Sapindus delavayi (Franch.) Radlk.,) plants are widely grown as shade trees in the subtropical to tropical regions of China. In July 2011, large, aerial galls were observed on the above-ground trunks of 5-year-old soapberry plants in two commercial nursery gardens located in Zhejiang Province. Disease incidence was estimated to be 75%. The galls varied in weight from 2 to 24 g and in texture from soft and spongy to hard, and in some cases, the galls completely girdled the trunk. The trees with galls exhibited poor growth compared with healthy trees. Isolations from the grinded and macerated galls yielded nearly pure white, circular, and glistening bacterial colonies on Roy Sauer medium (2). Six random colonies from different galls were selected for bacterial identification, and showed the same morphological, physiological, and biochemical characters and 16S rDNA sequences. All six isolates (isolate SD01 to SD06) were gram negative, rod-shaped bacteria. Carbon source utilization testing with the Biolog GN Bacterial Identification System (version 3.50) confirmed the bacteria as Agrobacterium tumefaciens with a similarity of 0.90. The most-parsimonious tree from the maximum parsimony analysis (PHYLIP package, version 3.68, 500 replicates) of bacterial 16S rDNA gene sequences showed that A. tumefaciens SD01 (GenBank Accession No. JX997939) clustered phylogenetically most closely (99.5% similarity) with A. tumefaciens C58 (AE007870.2). Pathogenicity was confirmed by injecting 3- to 5-week old tomato and sunflower plants and 2-year-old soapberry with approximately 5 μl of the bacterial suspension (10⁸ CFU/ml) in sterile, distilled water. Sterile distilled water was used as a negative control. Ten plants of each treatment were inoculated. Inoculated plants were then transferred to a greenhouse at 25°C. Typical tumors developed at the inoculation sites on tomatoes and sunflower plants 3 weeks after inoculation and on soapberry 6 weeks after inoculation. No symptoms were observed on the control plants. The bacteria that were readily reisolated from the inoculated plants exhibited the same morphological, physiological characters and 16S rDNA sequence as the original culture and were confirmed as A. tumefaciens, fulfilling Koch's postulates. A. tumefaciens is endemic to China and has a very wide host range (1). However, crown gall of soapberry has never been found in China and other countries. To our knowledge, this is the first report of A. tumefaciens on soapberry plants in China. References: (1) M. A. Escobar and A. M. Dandekar. Trends Plant Sci. 8:380, 2003. (2) L. W. Moore et al. Page 17 in: Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. N. W. Schaad et al., eds. The American Phytopathological Society, St. Paul, MN, 2001.

Isoflurane and sevoflurane increase interleukin-6 levels through the nuclear factor-kappa B pathway in neuroglioma cells

BACKGROUND

Isoflurane can increase pro-inflammatory cytokine interleukin (IL)-6 levels. However, the up-stream mechanism remains unknown. Nuclear factor-kappa B (NF-κB) promotes the generation of pro-inflammatory cytokines. We examined the effects of isoflurane and sevoflurane on the NF-κB signalling pathway and its association with IL-6 levels in cultured cells.

METHODS

H4 human neuroglioma cells (H4 cells), and mouse primary neurones and microglia were treated with 2% isoflurane or 4.1% sevoflurane for 6 h, for analysis of IL-6 and NF-κB. Pyrrolidine dithiocarbamate (an NF-κB inhibitor) or 2-deoxy-d-glucose (2-DG) (an inhibitor of glucose glycolysis) was applied 1 h before anaesthetic treatment.

RESULTS

Isoflurane or sevoflurane treatment increased the levels of IL-6 [isoflurane: 410% (54); sevoflurane: 290% (24)], the nuclear levels of NF-κB [isoflurane: 170% (36); sevoflurane: 320% (30)], and the transcription activity of NF-κB in H4 cells. Moreover, isoflurane enhanced the transcription activity of NF-κB in mouse microglia, but not primary neurones. Finally, pyrrolidine dithiocarbamate and 2-DG attenuated isoflurane-induced increases in IL-6 and NF-κB, and the transcription activity of NF-κB.

CONCLUSIONS

These studies in H4 cells suggest that the NF-κB signalling pathway could contribute to isoflurane or sevoflurane-induced neuroinflammation. This could lead to the targeted intervention of anaesthetic-induced neuroinflammation.

Abstract P5-10-10: The miR-34a is down-regulated in breast cancer and breast stem cells and a potential to eradicating breast cancer via a systemic delivery of a VISA –miR-34a nanoparticle system

Breast cancer is the most common disease in women around the world and the current treatment strategies are not potent enough for the patients, especially those who are the triple-negative type of molecular classifications. Therefore, novel and more effective treatments are pressingly needed. Of the current methods, target therapy, which not only retains cancer-specific expression but also limits toxicity, is a new strategy for treatment of cancers. In this study, it was to investigate miR-34a expression in breast caner specimen and its relationship with patient's clinical status, and develop targeted miR-34a delivery system as a potential method for breast cancer therapy. miR-34a expression was investigated by qRT-PCR and related to clinicopathologic significance and found to be down-regulated in breast cancer as compared with normal adjacent tissues and involved in breast cancer stem cell through down-regulation of CD44, ZEB1, and Bmi1. We designed targeted miR-34a expression using T-VISA system (hTERT promoter driven VP16-Gal4-WPRE Integrated Systemic Amplifier) liposomed-based nanoparticles and evaluated the antitumor effect in breast cancer cells in vitro and in orthotopic animal model as well as its systemic toxicity. The T-VISA-miR-34a system robust targeted to breast cancer cells and breast cancer stem cells and prolonged duration expression of miR-34a. Furthermore, a systemic delivery of a VISA –miR-34a nanoparticle system targeted efficiently expression of miR-34a to tumors and could significantly inhibit tumor growth and prolong mouse survival in multiple living imaging xenograft and syngeneic models of orthotopic breast cancer and without toxicity in intact mice. Our study demonstrated that miR-34a expression was down-regulated in breast cancer and breast cancer stem cells through down-regulation of CD44, ZEB1, and Bmi1. The T-VISA-miR-34a nanoparticle system showed robust antitumor effects in breast cancer and could be a potential therapeutic approach to eradicating breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-10-10.

PIKE mediates EGFR proliferative signaling in squamous cell carcinoma cells

One of the key drivers for squamous cell carcinoma (SCC) proliferation is activation of the epidermal growth factor receptor (EGFR), a known proto-oncogene. However, the mechanism of EGFR-dependent SCC proliferation remains unclear. Our previous studies indicate that epidermal growth factor (EGF)-induced SCC cell proliferation requires the SH3 domain of phospholipase C-γ1 (PLC-γ1), but not its catalytic activity. The SH3 domain of PLC-γ1 is known to activate the short form of nuclear phosphatidylinositol 3-kinase enhancer (PIKE) that enhances the activity of nuclear class Ia phosphatidylinositol 3-kinase (PI3K) required for proliferation. However, PIKE has been described for more than a decade to be present exclusively in neuronal cells. In the present study, we found that PIKE was highly expressed in malignant human keratinocytes (SCC4 and SCC12B2) but had low expression in normal human keratinocytes. Immunohistochemical analysis showed strong nuclear staining of PIKE in human epidermal and tongue SCC specimens but little staining in the adjacent non-cancerous epithelium. Treatment of SCC4 cells with EGF-induced translocation of PLC-γ1 to the nucleus and binding of PLC-γ1 to the nuclear PIKE. Knockdown of PLC-γ1 or PIKE blocked EGF-induced activation of class Ia PI3K and protein kinase C-ζ and phosphorylation of nucleolin in the nucleus as well as EGF-induced SCC cell proliferation. However, inhibition of the catalytic activity of PLC-γ1 had little effect. These data suggest that PIKE has a critical role in EGF-induced SCC cell proliferation and may function as a proto-oncogene in SCC.